This invention relates generally to wire gripping devices such as line splices and deadends and is particularly applicable to line splices and deadends of the sliding jaw type. More particularly, the invention is directed to a novel and improved end or center barrier for such devices.
Wire gripping devices of both the line splice and deadend type generally use serrated jaws or jawlike assemblies to grip a cable or conductor terminal end portion inserted therein. Such gripping devices generally include a tapered housing or shell within which such jaws or jaw assemblies having complementary tapered exterior surfaces are slidably mounted, so as to generally grip a wire or cable within the shell or housing. One such wire gripping device is shown and described in U.S. Pat. No. 3,172,180 to F. P. Baricevic et al.
A typical wire gripping device has at least one open end of the shell into which the conductor terminal end to be gripped is inserted. Usually, a pilot cup member is provided at the insertion end which encapsulates or surroundingly engages the terminal end of the conductor. The cup and conductor then passes through a serrated gripping jaw assembly, the external surfaces of which are tapered to correspond to an internal taper of the shell or housing. Typically, a spring or other resilient member is provided for normally urging the jaws in the direction of the housing or shell end opening. Accordingly, when the conductor has been inserted through the jaws, the latter tend to return toward the entrance, with the complementary tapers tending to close jaws about the cable. Hence, further outward pulling or tension upon the cable tends to pull the tapered jaws into an even more securely clamping condition about the cable, thus preventing removal thereof.
As mentioned above, such gripping assemblies or arrangements may be utilized either as a deadend or terminating device for a cable under tension, or to splice together ends of a pair of cables under tension. It will be understood, therefore, that the barrier of the invention is applicable to both types. That is, the invention may provide a barrier for either a deadend type gripping device or a center barrier for a bi-ended or wire splicing gripping device.
Typically, the cables to be terminated or gripped by such devices are provided wound up on reels.
Accordingly, as the cables are unreeled they tend to retain a generally curved set, bow or curvature. I have recently determined that this bow or curvature may cause the cable frictionally to engage the jaw assembly and to force or push the jaw assembly inwardly of the shell or housing as the conductor is inserted. Such movement of the jaw assembly may cause a total collapsing or compression of the compression spring by the jaw assembly, thus leaving the jaw assembly relatively closely axially spaced to an end wall or center barrier of the housing. In most such devices, the end wall or barrier defines an inward limit of the movement of the cable and pilot cup relative to the housing. In the case of bi-ended or splice-type gripping devices, the center barrier provides an end wall or stop surface for the cables entering the housing from both ends.
However, if the compression springs are collapsed such that the jaw end surfaces are closely axially spaced from the end or center barrier, the terminal end of the wire with the pilot cup engaged thereabout is precluded from moving fully through and clear of the jaws. Moreover, the installer, upon feeling the bottoming of the jaws within the housing or shell, assumes that the cable has been fully and properly inserted therewithin, clearing the jaws as is normally desired, when in fact the pilot cup has remained between the jaws. With the pilot cup lodged between the jaws, the jaws are prevented from developing the full desired grip on the cable or conductor. Such an incomplete grip can cause the device to fail in operation, releasing the grip on the cable, particularly when the cable is placed under tension, precluding the intended operation of the gripping device.
It is additionally possible that such incomplete insertion of the cable relative to the jaws and housing may occur from operator or installer error or use of improper technique. In any event, it is desirable that the effects of either cable curvature or installer error on the ultimate operation and reliability of the gripping device be substantially reduced. The novel barrier of the present invention facilitates this desirable result.